The Hamilton toddler who won Waikato's heart earlier this year with his courageous fight against an aggressive cancer pulls a face at his mum when she says he is a cheeky boy.

"No," Marley Marston says, a mischievous grin wiping across his face despite the tube running out his nose and across his cheek, and despite the multiple chemotherapy-induced ulcers making his mouth red-raw.

The Waikato Times first met the Marstons in March, when Laura Marston was eight months pregnant with Marley's brother London, and she was in desperate financial need.

People opened their hearts and their wallets to the family, and within days they had a reliable car, a warm house to live in and about $40,000 in a trust to help them focus all their attention on Marley.

That included enabling Miss Marston to take leave from the Hamilton East Medical Centre to help with her two grandsons, earning "one-quarter" of her usual income while she does.

And yesterday, HRV Waikato installed a ventilation system in the Marstons' Dinsdale rented home to make it a healthier place for Marley, who has a compromised immune system.

Managing director Lyndon Stewart said the positive-pressure ventilation system would flush highly purified air through anti-bacterial filters, helping to reduce the risks of infection by reducing moisture, toxins, bacteria and volatile organic compounds.

As usual, the Marstons were grateful for all the help they had received.

Miss Marston said that before last week Marley had had nine weeks off his treatment, something she and the doctors decided was worthwhile to enable the whole family to enjoy time together after London was born.

"They were precious memories we could never replace," Miss Marston said.

During that time Marley seemed healthier as he was not suffering the side-effects of his treatment, and he enjoyed a Buzz Lightyear-themed second birthday and more time with his dad, with whom Miss Marston said her interactions were slowly improving.

Miss Marston said she had always avoided Googling Marley's illness until recently.

"I've always just listened to what the doctors said but not thought about what they're not saying."

She realised that in Marley's current condition, the bone marrow transplant that will hopefully take place in October will have just a 10 per cent chance of success.